Looks to me like a nucleophilic acyl substitution, with attack at the Br centre and stabilization of the intermediate by extensive conjugation and charge stabilization due to negative charge landing on electronegative nitrogens. Expulsion of Br should give KBr as a nice solid.

May be the substrate can be considered as imidoyl bromide analogue, and accordingly the mechanism would involve addition-elimination sequence, the addition part being facilitated by delocalisation of the negative charge over two N-s
And, BTW, what does ANRORC stand for?